BOSTON: Sounding eerily like Bob Dole, William Weld resigned a job he seemed born to hold in order to fight a steep uphill battle for a position he has slim odds of winning. In stepping down as Governor of Massachusetts to fight Jesse Helms' opposition to his appointment as ambassador to Mexico, Weld said simply, "I don't believe it would be fair to the people of Massachusetts to permit the conduct of their government to become embroiled in the vagaries of Washington politics." Weld now finds himself alienated both from the President who nominated him and his own Republican party, having publicly blasted Jesse Helms for engaging in what he called "ideological distortion," and Clinton for seeming to back away from the fight. It's hard to see how he thinks he is going to win this one. While Helms says his opposition to the posting turns on Weld's past support for the medicinal use of marijuana, and has suggested that Weld might be perfect for a place like, say, New Delhi, it is Weld's liberal social views that have made him anathema to the most conservative leaders of his party. For Clinton, the real value of the appointment was getting Weld out of the Massachusetts governor's office so that a Democrat -- say Joe Kennedy, who wants the job -- would not have to run against the extremely popular Republican moderate. Now that Weld's stepped down, the President has little to gain by getting involved in the GOP's family fight.